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Kohler carb butterfly sticking only when engine is running.


LawnSite Member
Hey folks!
This one has me stumped big time. It's a 20hp kohler model MV20s, apposed twin.
Here's what's happening. While the engine is running the throttle butterfly gets very hard to turn. While the engine is off the butterfly turns freely. This is with the governor linkage disconected. You can literally run the engine without the linkage and the throttle butterfly will stay locked in place. I've went as far as replaceing the carb with a new one and have the exact same results. This happens weather the engine is cold or warm.


LawnSite Bronze Member
Gambrills, MD
O.K. misunderstood the problem. First thing to do is to get a copy of the owners manual, and the parts manual. See if the carb linkages are pointing the right way. If this is a new (to you) unit it it is possible that someone put the original carb together wrong. I'm not saying that this is the correct or only answer, but I have seen it happen before. I've gotten so bad at remembering how things go together, that I take digital pics of what I am working on before I remove a major assembly, so there is no chance that I can forget how to put it together again!

Bill Kapaun

LawnSite Senior Member
Albany, Orygun
You'll have to figure out if the butterfly is binding in the carb bore or the shaft is binding.
The fact it's doing it on a new carb also with all the linkage disconnected is VERY strange!
Is the flange the carb mounts on distorted/warp/chunks of old gasket causing the carb body to distort when bolted down?

I couldn't find the manual for the M series at Kohlers web pages, but found this old link that seems to work.